engleski

Impact Of Wastewater Effluents And Contaminated Sediments On Zebrafish Embryos Using Multiple Endpoint Testing

Wastewaters and sediment contamination are important factors influencing various ecosystems and human communities around the world. The increase of human population, world living standards, rapid urbanization and climate change are putting pressure on our most important natural resources: water and soil which are at the core of sustainable development. They are critical for socio-economic development, environmental well- being and human health. The number of toxic compounds that are released into the freshwater, marine and land ecosystems have increased significantly over last few decades. Contaminants accumulate in sediment and act as long-term, secondary sources of toxicants while wastewater effluents are complex mixtures of various organic and inorganic substances suspended and dissolved in water. Samples of wastewater were taken from wastewater treatment plant near Virovitica, Croatia, while samples of sediments were taken at 4 different parts of Sava River. Physical and chemical parameters have been measured for wastewater effluent, while the method used for detection of contaminants in sediments was chemical analysis of non-target organic compounds. Toxic effects of wastewaters and contaminated sediments were tested on zebrafish Danio rerio embryos using a set of biomarkers that gave us insight into toxic potential at the cellular, tissue and the whole organism level during early ontogenesis. Biomarkers that were used are Zebrafish Embryotoxicity Test (ZET), comet assay for genotoxicity assessment and histopathological analysis. Exposure of embryos resulted in increased mortality and abnormality rate at both 24 and 48 hours post fertilization. Various lethal and subletal effects were observed with both ZET and histopathological analysis, such as lack of pigmentation, brain and muscular necrosis, notochord malformation, retardation in eye development, pericardial and yolk sack oedema, etc. Comet assay evidently showed that tendency of DNA damage increases near locations of increased pollution. Combination of the chemical analysis with histopathological biomarkers, ZET and comet assay could serve as a guiding principle in biomonitoring of wastewater and sediment contamination.

Danio rerio, Wastewater, Zebrafish Embryo Test, Comet assay, Histopathology

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